Membrane fractions derived from fractionation of myelinated axons in a zonal rotor will be used to raise antibodies. The antigenic sites for the antibody will be identified morphologically and biochemically. The functional role for proteins found in the membrane fraction which has been identified as axolemma-enriched will be established by two-dimensional fingerprinting and comparison with the fingerprint of proteins having a known function. The mitogenic signal in these membrane fractions will be further studied to establish whether or not the mitogenic effect is cyclic AMP-mediated, whether or not the membrane fractions must be internalized prior to exerting their mitogenic effect. Finally, the molecular nature of the interaction between the axolemma-membrane fraction and the glial cell will be explored by observing how specific alteration in the surface of each membrane affects the expression of the mitogenic signal.